Catalysts for polymerization reaction



latented July 31, 1945 CATALYSTS FOB POLYMEBIZATION REACTION William D. Stewart, Akron, Ohio, assignor, by

Goodrich mesne assignments, to The B. I".

Com-

pany, Akron, Ohio, a corporation of New York No Drawing. Application October 22, 1941,

Serial No. 416.087

12 Claims. (01. 280-8445) This invention relates to the polymerization of unsaturated organic compounds which are cap- Nn- -Nn able of undergoing an addition polymerization to form high molecular weight linear polymers. and particularly to the polymerization in the form 5 Hydmm of an aqueous emulsion of a butadiene either 0 alone or in admixture with a monemer 1 0 3" J merizable therewith The principal object of the 1 invention is to provide a method for decreasing O: =0 the time required to eflect such polymerization l0 Barbituric acid reactions.

I have discovered that the time required to efga g gs zga g gf wgf g gx i'ect polymerization reactions mayfbe decreased alysts tosgeed 5 the polymerization by polymerizing unsaturated organic compolmds The referred methods of practicingthisinvenin the presence of a compound containing the on 5 be shown by the following specific gmup x amples which illustrate rather than limit the g invention. Example: I, II, and III where R represents an acidic group and X repre- A mixture containing 55 pm by weight of one the groups =0 and may butadiene, 4.5 parts of acrylonitrile, about 9* any desired acidic group and may or may not parts of a 2% solution 01' myristic acid which had zorm part of a ring structure. Groups containbeen 85% neutralized with sodium hydroxide ing a doubly or triply bonded carbon atom such as (L035 pm of hydrogen peroxide and m6 pm f or 25 dlisopropyl dixanthogen was agitated at 0. s The polymerization required 20 hours to reach connected to the nitrogen either directly or by g gg z gi i g :535: gr g; a single carbon atom are preferred acidic groups' titl i e req red ior the po l gmeri ation i2 0 reach ggf g 5 giggzfig gi fisim gg 30 completion to 14 hours, and a like reduction in the time required was achieved by the use oi only 0.015 part of creatlne. The products prepared NH,CNHC-NH: in the presence of the catalysts exhibited excellent which may be employed a a or in the {OI-m milling properties and formed vulcanizates exof a mineral acid salt such as human-med with hibiting high tensile strengths and elongations. hydrochloric or sulfuric acid. Other materials The Pmducts resisted 011 and 1181011 include 7 marked degree, and were capable of use not only NH as a replacement for natural rubber but also in compositions where rubber cannot be employed 5 40 because of its inherent defects. mcymdhmm The catalysts or this invention may also be emi m ([313, ployegs in conjuufiction 311th heavy metal comoun in w c case e polymerization pro- NH' C N 9 OH eeed more rapidly than when either catalyst is 0M1"! employed alone and the system will tolerate con- 0 NH H, 0 siderably higher proportions oi heavy metal. The I LL use of heavy metal compounds as catalysts is claimed in applicant's copending application 8e- 05 riaLNo. 379,712 flied February 14, 1941. As thereis disclosed, the term heavy metal is used to sigcn; NH niiy metals which have a low atomic volume (ratio of atomic weight to density) and consequently appear substantially at the minimum points on Lothar Meyer's atomic volume curve. The metals Creatinino 56 appearing in group VIII, subgroup B of groups I andmandsubgroupAoigro psVIandVlIare accordingly among th metals included in the term heavy metal. The metals or group VIII, particularly iron, cobalt, and nickel, are prei'erred.

Example IV a mixture of '1 parts of butadiene, 3 parts of styrene, about 25 parts of a 2% solution oi myrls- It may also be advantageous to employ one of the catalysts of this invention in the presence of two heavy metals. When 0.025 part of dicyandiamidine sulfate, 0.005 part of ferric alum, and 0.0005 part oi cobaltous chloride were employed as the catalyst in a recipe like that described in Example IV, the polymerization was complete in 14 hours.

Although the preferred method of polymerization is by an emulsion polymerization as set forth in the specific examples, the catalysts herein described may be employed to accelerate the rate of polymerization in homogeneous systemsin the presence or absence of solvents or diluents in the manners well known to the prior art.

The catalysts of this invention may be employed in widely varying proportions. The use of from 0.1 to 0.5% by weight based on the polymerizable materials ordinarily gives a pronounced catalytic eflect. Noticeable eilects are produced by the use oi lower concentrations, although the optimum amount for the greatest catalytic eflect is ordinarily above 0.1%. Greater amounts such as 1% or more can in general be employed, if desired, without any detrimental eilects. Although less than 0.1% or heavy metal compound, preferably in the form of a water-soluble salt is ordinarily employed, the catalysts of this invention which form complexes with heavy metal compounds permit the use of a greater concentration or heavy metal than can be employed in the absence 01 any complex-forming compound. The complex-forming compound and the heavy metal compound may be added separately to the monomers prior to the polymerization, or may be reacted to iorm a heavy metal complex before they are added to the monomers.

The catalysts of this invention may be employed in the polymerization of any unsaturated organic compounds which are capable of undergoing an addition polymerization to form a high molecular weight linear polymer. Included in this class of monomers are the butadienes-l,3 such as butadiene-l,3 (commonly termed butadiene) isoprene, 2,3-dimethyl butadiene, piperylene, and chloroprene; aryi oletins such as styrene, vinyl naphthalene, and alpha-chlorostyrene: acrylic and alpha-substituted acrylic acids, esters, nitriles,

, and amides such as acrylic acid, acrylonitrile,

alpha-methacrylonitrile, alpha-chloracrylonitrile. methyl acrylate, methyl methacrylate, methacrylamide; vinyl halides, esters, ethers, and ketones such as vinylidene chloride, vinyl chloride, vinyl vinyl ether. Any of the above compounds all of which contain a group may also be ccpolymerized with monomers copolymerizable therewith. Butadiene, for instance, may be copolymerized with one or more monomers which enter into the polymeric chains by 1,2-addition such as acrylonitrile, styrene, methyl acrylate. etc.

As emulsifying agents which may be employed in emulsion polymerizations may be mentioned soaps such as sodium oleate, potassium palmitate, and sodium myristate, synthetic saponaceous materials including hymolal sulfates and alkaryl sulfonates such as sodium lauryl sulfate and sodium isopropyl naphthalene sullonate, and salts or organic bases containing long carbon chains such as the hydrochloride or diethylaminoethyloleyiamide, trimethylcetylammonium methyl sulfate, the hydrochloride 0! oleylamidoethyldimethylamine, and the hydrochloride oi the diethylaminoethoxyanilide of oleic acid. The soaps are employed in polymerizations under basic conditions, the salts of organic bases under acid conditions, and the synthetic saponaceous materials under acid, alkaline, or neutral conditions.

The polymerization may be effected by various known initiators of polymerization such as pe compounds including hydrogen peroxide, benzoyl peroxide, ammonium persuliate, potassium persuli'ate, and other peroxides and persalts such as persultates, perborates, percarbonates, and the like, as well as other types of initiators such as diazoaminobenzene, sulfur dioxide, hyposuliltes, bisulfltes, dipotassium diazomethane disulionate, and triphenylazobenzene. The polymerization, particularly ii. conducted homogeneously, may also be initiated by actinic radiation.

The plasticity and solubility of the polymers produced by homogeneous polymerizations may be increased by including in the charge chlorinated compounds such as carbon tetrachloride and trichloracetic acid, while a corresponding eiiect can be obtained in emulsion polymerizations through the use of sulfur-containing compounds such as the dialbl dixanthogens, the

higher tetraalkyl monoand polysulildes, merv captoalkylthiazoles, etc.

Other methods and procedures known to be usemi in connection with the polymerization oi unsaturated organic compounds are within the spirit and scope of the invention as defined in the appended claims. 0

I claim:

1. The method which comprises polymerizing in the form of an aqueous emulsion a mixture comprising butadiene-L3 and a monomer copolymerizable therewith in aqueous emulsion, in the presence oi! a mixture 01 dicyandiamidine and a water-soluble salt of a heavy metal or group VIII.

2. The method which comprises polymerizing in the form or an aqueous emulsion a mixture comprising butadiene-1,3 and, acrylonltrile in the presence of dicyandiamidine.

8. The method which comprises polymerizing in the form of an aqueous emulsion a mixture comprising butadiene-1,3 and styrene in the presence of dicyandiamidine.

4. The method which comprises polymerizing, in the form or an aqueous emulsion, a mixture of butadiene-1,3 and styrene in the presence of a heavy metal complex containing a heavy metal acetate, methyl isopropenyl ketone, and methyl oigroupVIIIa-nd dloyandiamidine.

5. The method of claim 4 in which the heavy metal is iron.

6. The method of claim 4 in which iron and another heavy metal are employed.

'1. The method which comprises subjecting an unsaturated organic compound which contains a roup and undergoes in aqueous emulsion an addition polym rization to form a high molecular weight linear polymer, to addition polymerization in aqueous emulsion in the presence of dicyandiamidine.

8. The method which comprisessubjecting an unsaturated organic compound which contains a CH C group and undergoes in aqueous emulsion an addition polymerization to form a high molecular weight linear polymer, to addition polymerization in aqueous emulsion in the presence of a watersoluble salt 01' a heavy metal and dicyandiamidine.

9. The method which comprises subjecting an unsaturated organic compound which contains CH|=C/ I group and undergoes in aqueous emulsion an addition polymerization to form a high molecular weight linear polymer, to addition polymerization in aqueous emulsion in the presence of a watersoluble salt of a group VIII heavy metal and dicyandiamidine.

10. The method which comprises polymerizing cyandiamidine.

WILLIAM D. STEWART. 

